The role of cytokines and adhesion molecules in maternal recognition and establishment of pregnancy in pig.

摘要

Oestrogen synthesis and release by day 11 conceptus is known as the main signal for the maternal recognition of pregnancy in the pig. The maternal recognition and subsequent establishment of pregnancy require a complex network of interactions between embryo and uterus. Both embryo and uterus secrete various signaling molecules, all of which are necessary for the initiation of the foeto-maternal relationship. Many of the events during peri-implantation period have an inflammatory character, therefore are accompanied by increased amounts of cytokines. Porcine conceptus expression of interleukins and other cytokines have been reported. Pregnancy-specific endometrial expression of leukaemia inhibitory factor (LIF) is initiated during the conceptus elongation and can affect conceptus development. Moreover, enormous antiviral activity, coordinated with increased interferons secretion, has been detected at the time of blastocyst implantation in pig. This prolonged pre-receptive period is followed by implantation which results in conceptus attachment to the uterine epithelium. Adhesion to the uterine epithelium is controlled mainly by integrins but also other adhesion molecules such as Mucl, Muc 4 or osteoponin, have been implicated in the porcine implantation cascade. Since there is increasing amount of evidence that cytokines and adhesion molecules are crucial for interactions between conceptus and uterus, we decided to present the discussion on their role in recognition and establishment of pregnancy in the pig. This review may help to understand better mechanisms occurring in the peri-implantation period in pigs..